This invention relates to a bar-code reader use in the EPOS system and the like.
Bar code symbolic systems are categorized as the JAN code, EAN code and UPC code systems, each composed of a fixed number of stripes and intended for retail commodities, and the Code39, Code128, NW7 code and ITF code systems, each composed of an unfixed number of stripes and intended for the FA, wholesale and OA industries. In addition, there are two-dimensional bar code systems including a multi-stage bar code system which is composed of the above-mentioned various code symbols arrayed in multiple stages, and the Code49 system which is composed of sets of a fixed number of stripes arrayed in a number of stages ranging from two to eight.
As a means of reading bar code symbols of a fixed number of stripes, bar-code readers based on the image sensor have been used more prevalently as compared with pen-type bar-code readers. Bar code price labels are attached to a variety of retail commodities, such as canned goods and cloth products, which do not necessarily have hard and flat surfaces. Therefore, cashiers often prefer the bar-code reader based on the image sensor which bases the operation on electronic scanning across a bar code through its reading window having a focal depth of 10 mm or more by being kept stationary on the label, rather than the pen-type bar-code reader which needs to trace a bar code at a constant speed by being in contact with the label.
On the other hand, bar code symbols with unfixed numbers of stripes can extend as long as 15 to 20 cm, and are printed directly or labeled on hard and flat surfaces. Therefore, the pen-type bar-code reader is often used, rather than the image sensor based bar-code reader which suffers the bulkiness and poor operability and accuracy in dealing with long bar code labels.
As a result of recent development of bar code applications, bar code symbols based on the JAN, EAN and UPC code systems labeled on such soft surfaces as cloth products and bar code symbols of unfixed lengths based on the Code39, Codel28, NW7 and ITF code systems appear mixed in the retail, FA, OA and wholesale industries. Consequently, bar code users have to prepare two kinds of bar-code readers, i.e., pen type and image sensor type, attain the connectivity of two kinds of readers to a host machine, and select one of the devices depending on the kind of bar code. These problems are considerable barriers against the progress of bar code applications.